R/tradeoff.R

In pid: Process Improvement using Data

# DONE: Ensure that there is 1 or more entries in the list; pick the first one
# DONE: what happens if a full factorial is requested
# DONE: what happens if a "twice" or "four times" is requested
# TODO: add the defining relationship as an output. There are 2^p words in that
#       relationship.
# TODO: allow the user to specify the factor names in a list, and use these instead.
tradeoff <- function(runs=8, factors=7, display=TRUE){

  if (as.integer(runs) != runs) {
    stop('The "runs" input must be an integer.')
  }
  if (as.integer(factors) != factors) {
    stop('The "factors" input must be an integer.')
  }
  if (!requireNamespace("FrF2", quietly = TRUE)) {
    stop(paste0("Package \"FrF2\" is essential for this function to work. ",
                "Please install it."), call. = FALSE)
  }
  if (!requireNamespace("FrF2.catlg128", quietly = TRUE)) {
    stop(paste0("Package \"FrF2.catlg128\" is essential for this function to work. ",
                "Please install it."), call. = FALSE)
  }
  if (!requireNamespace("DoE.base", quietly = TRUE)) {
    stop(paste0("Package \"DoE.base\" is essential for this function to work. ",
                "Please install it."), call. = FALSE)
  }


  # Use FrF2 catalog to locate the experiments
  cat.entry <- FrF2::catlg
  subset_runs <- FrF2::nruns(cat.entry) %in% runs
  subset_factors <- FrF2::nfac(cat.entry) %in% factors
  if ( (sum(subset_runs * subset_factors)) == 0) {
    stop("The number of runs and/or number of factors do not specify a fractional factorial.\n
         Please type: tradeOffTable()\n         for assistance.")
  }else{
    joint <- cat.entry[as.logical(subset_runs * subset_factors)]
  }
  joint <- joint[[1]]
  resolution <- as.character(as.roman(joint$res))

  if (display){
    pr.header <- paste0("With ", runs, " experiments, and ", factors, " factors:\n")
    pr.res <- paste0("  Resolution: ", resolution, "\n")
    cat(pr.header)
    cat(pr.res)
  }
  # Fractional factorial experiments have 2^{k-p} number of runs,
  # where factors == k and ngen == p.
  ngen  <- factors - log2(runs)
  the.catalog <- FrF2::FrF2(nruns = runs, nfactors = factors)
  aliasing <- attr(the.catalog, "design.info")
  gen <- DoE.base::generators(the.catalog)
  if (display){
    if (ngen > 1){
      pr.gen <- paste0("  Generators:\n")
      for (elem in gen$generators){
        pr.gen <- paste0(pr.gen, "      ", elem, "\n")
      }
    }else{
      pr.gen <- paste0("  Generator: ", gen$generators, "\n")
    }
    pr.alias <- paste0("  Aliasing (related ONLY to main effects and 2-factor interactions):\n")
    if (resolution != "III"){
      #length(aliasing$aliased$main)==0) is an alternative test
      pr.alias <- paste0(pr.alias, "      Main effects are not aliased with 2-factor interactions.\n")
    }else{
      #pr.alias <- paste0(pr.alias, "    Main effect aliasing is:\n")
      for (elem in aliasing$aliased$main){
        pr.alias <- paste0(pr.alias, "      ", elem, "\n")
      }
    }

    if (length(aliasing$aliased$fi2) > 0){
      #pr.alias <- paste0(pr.alias, "    Two factor aliasing is:\n")
      for (elem in aliasing$aliased$fi2){
        pr.alias <- paste0(pr.alias, "      ", elem, "\n")
      }
    }

    pr.alias <- paste0(pr.alias, "\n")

    # Show the generator section and the aliasing section.
    cat(pr.gen)
    cat(pr.alias)
  }
  invisible(list(resolution = resolution,
                 generators = gen$generators,
                 aliases = aliasing$aliased))
}
if (FALSE) {
  tradeoff(runs = 8,  factors = 4)
  tradeoff(runs = 8,  factors = 5)
  tradeoff(runs = 8,  factors = 6)
  tradeoff(runs = 8,  factors = 7)
  tradeoff(runs = 16, factors = 5)
  tradeoff(runs = 16, factors = 6)
  tradeoff(runs = 16, factors = 7)
  tradeoff(runs = 16, factors = 8)
  tradeoff(runs = 16, factors = 9)
}